Smokeless explosive powder



Patented May 10, 1927.

un te!) STATE PATENT"; or fice.

rumors I. nu rom Am). nmsr nurour, or wmrmm'ron, nntawnnn, assrenoes no u. s. r. rownnn comm, or wrnmme ron, nntawnnn, A couronamou on I l lo '11: applications filed by us April 24, 1920- (as Serial No. 376,267), and January 24, 1919 (as Serial No. 272,857), we have set forth smokeless explosive ordnance powders with a progressively increasing rate of burning which, when used as a propellant in a. gun, very materially reduce, or approximately eliminate, the muzzle flash. These e losives comprise a colloided mass of nitrocel ulose containing one-half of one per cent to twenty per cent of particles of a flame propagating agent so thoroughly distributed I throughout the'mass that it carries the flame from the exposed surfaces, through a multi- 5 tude of minute channels, into. the interior of the powder grains, thereby efiecting a progressively accelerating combustion by bringing all the particles of the colloided nitrocellulose much more speedily into contact with the tire (and effecting an earlier com-- plete-consumption of the powder than is the case where 'relianceis had solely upon the usual large and relatively coarse mechanical .perforation employed in this type of ord- 5 nance powder. In this invention another type of burning is superimposed u on that afi'orded by these mechanical. per orations.

The acceleration 'ofburning is such thatthe'powder is substantially consumed, that is, combustion and heat' development substantially cease, before the gaseous mass emerges from the muzzle of the gun. The

i work doneand the expansion cool substan tially the emergin' .g-un massfand flash does notoccur.-..Th e. flame propagating agents disclosed 'in said applications have the proprty .of. much expediting the consumption of the nitrocellulose-without materially invcreasingthechamber pressure (thus avoid eroslon of the gun barrel), without ser ously fouling the gun and without-excess of smoke. The said applications, in addition to .disclosing certain operable vflame propagating agents and the. proportions '4 thereof necessary or advisable to use, disclose apracticable processof incorporating the ingredients; this process in substance consisting in making an intimate mechanical mixtureof nitrocellulose and the agent and then colloiding thenitrocelluloseto convertit an integral or continuous m'ass enclosing the particles of said agent. The specific Inateri ls that we have heresmoxnnnss nxrnosrvn rownnn. V a iieaaonaiq February 23,1921. serial No. 447,229.

tofore found to be capable of effective use asflamepropagating agents and which are disclosed in said applications are ordinary black meal powder, or a mixture ofbarii nitrate and potassium nitrate.

-VVl1ile the characteristics of-these two 'fire propagating agents are quite dissimilar, the first, for example, being a complete explosive, whilethe latter has an excess ofoxygen, both agentsare thoroughly efficient to accomplish the objects sought, namely, that of preventing flash with a nitrocellulose explosive containing them.

The object of the presentinvention is to provide a flame propagating'agent having the functions and advantages of thespecific propagating agents disclosedin said'applications and which will have the additional advantage of rendering the' explosivemorc stable. 7

We have discovered that by the useof a mixture of potassium bichromate and charcoal, incorporated with the nitrocellulose by means of the process described in the said applications, a flashle'ss smokeless propellent explosive ordnance powder is produced that fully attains the object sought. 'lVe have also discovered that potassium bichro--" mate alone is effective to secure the results' de sired, so that the additionpf charcoal is not essentiah although it has the advanta e of taking up the excess of oxygen in t 1e flame propagating agent if that excess be deemed undesirable. That is, potassium bichromate, when used alne, has the quality, in common with 'a mixture of barium nitrate and. potassium nitrate, of evolving a certain amount ofoxygenr When charcoal is added. in sufficient proportion to' potassium bichromate, the oxygen content of the mixture is balanced out by the carbon added and the mixture corresponds to black powder; which we have found an eflicient agent.

The finished explosive,,containingpotassium bichromate, with or without charcoal, asthe flame propagating agent, is more stable than :the same explosive containing, either a mixture of potassium "nitrate and barium nitrate, or. black powder, as the flame propagating agent; so that it will 'be understood that the present; invention by dryin for those heretofore described by us, but pro-.-

actually an improvement upon the specific fflashless explosive powders set forth in our said prior applications.

- The method of manufacture is, preferably, the same as that described in said prior applications. The flamepropagatingagent is added to soluble nitrocellulose, wetted with about thirty per cent of a suitable liquid, such as Water or gasoline, to facilitate blending, and incorporated therewith in a standard black powder wheel mill. This results in a mechanical mixture of the two bodies. The added liquid is thenexpelled.

"or otherwise. The. colloiding agents, at er and alcohol, are then added and the entire mixture is thoroughly col-' loided in akneading machine; After the powder has been formed into grains of the usual type employed in, ordnance, a considerable proportion of alcohol and other is distilled ofi, a certain proportion: remaining Lduce' mere porosity 1n the finished Porosity, or porosity alone, is not desired, 3o

' tion of the.

in the finished product.v Care should be taken to avoid removing the alcohol and ether in any way whichwoulcl remove the.

fire propagating agent, as that would proproduct.

but what is desired, and what is secured by theforegoinprocess, is a proper disseminae ropagating agent'through= out the colloide mass of the nitrocellulose.

The flame propagatingagent may eonsti tute from oneto fifteen per cent'or the en-* tire explosive: Where potassium bichromate alone is used as the flame propagating agent, it is not desirable that its proport on should exceed, ten per cent. About-five per cent is preferred. Where a,, mixture of potassium bichromate and charcoal is used, while there is no objection to the use of as high as. fifteen per cent of the mixture, about four per cent is preferred. In this mixture we prefer to use a preponderating proportion of potassium bich'rom'ate. Seventy-five per cent of the latter and twentyfive per cent of charcoal have been tound efficacious. The proportion of charcoal in rovide' sufiicientcarbon to balanc th o d'uces a flashless smokeless powder that is e 6 xy gen content- Wood charcoal is preferred.

.Where in the claims, we mention colloided nitrocellulose, we use that "term in the sense in which-it is ordinarily used by .those'skilled' in the art, namely: nitrocellulose which has been dissolved to a solution tirely different: from: that which ithad befor solution;

Having now what we claim and'desire to protect by Let ters Patent is; a g V p I. A flashless smokeless propellent pow- I a der which comprises a preponderating proportion of completely colloided nitrocellulose containing a relatively small proportion of a flame propagating agent comprising. potassium bichromate uniformly distributed 1 throughout the mass ofthe nitrocellulose.

ing. a relatively small proportionof potassium bichromate and charcoal distributed throughout the mass of the nitrocellulose.

fully describeclour invention, a

2. A *flashless smokeless'propellent pow a a der: which comprises a preponderating pros .portion of colloided nitrocellulose containa Aflashlesssmokelesspropellent powder which comprises from eighty-five to nitrocellulose containing from one to fifteen per cent of. a flame propagating agent comprising potassiuni bichromate uniformlyf a distributed throughoutthe mass.- p I 4-. A flashless.smokelesspropellant powder which comprises from eight five to lose containing from oneto fifteen per cent of a -mixture of potassiumbichromate and charcoal. I

, 5. A flashless smokeless propellent powder which comprises a preponderating proportion of colloided mtrocellulose having In testimony of which invention, we have the mixture incorporated into the'nitrocel hereunto set our hands, at. Wilmington,

lulose may be increased to as high as fifty per cent and may be reduced to as low as about eight per cent. A substantially smaller PIQPOI'HOII, of charcoal would not Delaware, on this 18th day of, February,

FRANCIS I. DU PONT,

ERNEST nu FONT.

nihety-fiv'e-per cent of completely colloided ninety-nine per cent of colloided mtrocellu-.z 

